1. Field of the Invention
The present invention relates to an electric junction box for use for distribution of an electric system of an automobile or the like therein, and more particularly to an electric junction box in which a group of male terminals provided on a bus bar in such a manner as to erect therefrom and a group of male terminals provided on an associated electronic unit in such a manner as to erect therefrom are connected to each other via a group of relay female terminals.
2. Related Art
Conventionally, various types of junction boxes have been in use for distribution of an electric system of an automobile or the like therein. For instance, referring to FIGS. 7 to 9, a conventional assembling construction will be described in which a relay terminal is assembled to a conventional electric junction box. As shown in FIGS. 7 and 8, in a conventional electric junction box 51, a first group of male terminals 4 provided on a bus bar 3 on a laminated electric distribution substrate 2 in such a manner as to erect therefrom and a second group of male terminals 6 provided on an associated electronic unit 5 such as a relay unit in such a manner as to erect therefrom are connected to each other via a group of relay female terminals 57.
To be more specific, terminal receiving chambers 59 made to open toward a bus bar 3 are provided in a cover 58 covering an electric distribution substrate 2 for holding relay female terminals 57. In addition, an insertion through hole 60 having inclined guide surfaces for the second male terminal is formed in a ceiling portion of the terminal receiving chamber 59, and a fit holding groove 62 is formed in a portion above the ceiling portion for holding an electronic unit 5 fitted therein at external walls of the electronic unit.
FIG. 9(a) is a side view of the relay female terminal 57, and FIG. 9(b) is a plan view thereof. This relay female terminal 57 is formed by folding a metal plate having high electrical conductivity and corrosion resistance such as a brass plate. Sides of a bottom plate 63 are bent to form side plates 64, 65 and one of the side plates, which is the side plate 65, is further bent to form a ceiling plate 66, thus the relay female terminal 57 being formed into a box-like configuration as a whole.
In addition, the side plate 64 is also partially bent over the ceiling plate 66 so as to form a positioning projection plate 67 which is adapted to be brought into engagement with a positioning groove 59a provided in the terminal receiving chamber 59. Moreover, a boundary groove 70 is formed in the ceiling plate 66 between a first female terminal portion 68 adapted to be inserted over a first male terminal 4 and a second female terminal portion 69 adapted to be inserted over a second male terminal 6. Furthermore, the ceiling plate 66 is inwardly bent at ends thereof to form first and second elastic contact pieces 71, 72 which are adapted to be brought into contact with the first and second male terminals 4, 6, respectively.
In the electric junction box 51 constructed as described above, a cover 58 is placed in position after the first female terminal portions 68 of the respective relay female terminals 57 are securely inserted over the first group of male terminals 4 provided on the electric distribution substrate 2 in such a manner as to erect therefrom. When this is performed, the cover has to be so placed while the group of relay female terminals 57 provided erectly on the electric distribution substrate 2 are being aligned with the terminal receiving chambers 59 and positioning grooves 59a provided in the cover 58. Then, when the electronic unit 5 is securely mounted in the fit holding groove 62, the second male terminals 6 are brought into contact with the second elastic contact piece 72 within the second female terminal portion 69, whereby the bus bar 3 and the electronic unit 5 are electrically connected to each other.
Furthermore, since there is contemplated a positional tolerance of the first group of male terminals 4 and second group of male terminals 6 relative to the position of the group of terminal receiving chambers 59, the relay female terminal 57 is constructed so as to be loosely fitted in the terminal receiving chamber 59 to thereby correct a positioning error.
In the above conventional electric junction box 51, however, when the large cover 58 is placed over the electric distribution substrate 2, with a small pitch between the first male terminals 4, there exists a problem that engagement of the group of relay female terminals 57 within the terminal receiving chambers 59 becomes difficult and hence the working efficiency is deteriorated.